1. Field of the Invention
Exemplary embodiments relate to a method for effectively protecting protocol header information in a system in which a high-speed transmission is performed using an ultra wideband frequency band, and more particularly, to a frame generation method that may protect header information having a variable length.
2. Description of the Related Art
A Reed-Solomon (RS) code is a Forward Error Correction (FEC) technique that may be widely used in various application fields such as mobile communications, magnetic storage, optical storing media, wired and satellite communications, and the like. An RS (255, 239) code or an RS (224, 216) code may be used in a 60 GHz Millimeter Wave (mmWave) wireless communication system.
In general, a shortened RS code scheme, that is, an RS code scheme may have 255-numbered information bytes or 224-numbered information bytes as a mother code, and may add 239-numbered bytes or 216-numbered bytes, having a value of ‘0’, after the information byte. Using the information bytes in which the byte having the value of ‘0’ is added, an RS parity bit having a bit length of 16×8 or 8×8 may be generated according to an RS FEC scheme, and the generated RS parity bit may be added after the information bytes. In this instance, the bytes having the value of ‘0’, which are added after the information bytes, may be removed.
A shortened Low Density Parity Check (LDPC) code scheme, similar to the shortened RS code scheme, may be used in the 60 GHz mmWave wireless communication system. The shortened LDPC code scheme may have 672-numbered information bytes as a mother code, and add 336-numbered bytes, having a value of ‘0’, after the information bytes. Using the information bytes in which the byte having the value of ‘0’ is added, an LDPC parity bit may be generated according to the LDPC code scheme, and the generated LDPC parity bit may be added after the information bytes. In this instance, the bytes having the value of ‘0’, which are added after the information bytes, may be removed.
A conventional Single Carrier (SC) physical layer protocol (PHY) standard may encode a PHY header, a Media Access Control (MAC) header, a Header Check Sequence (HCS) field using the above described shortened RS code scheme. In this instance, the PHY header, the MAC header, and the HCS field for error detection of the MAC header may designate a basic header of a frame (hereinafter, referred to as basic header”). An MAC subheader and the HCS field may be encoded using the shortened RS code scheme. In this instance, the HCS field for error detection of the MAC subheader and another MAC subheader may designate a selection header of a frame (hereinafter, referred to as “selection header”).
However, a conventional selection header in which the above described shortened RS code is used may have a variable length. Accordingly, the variable length may cause a problem in that an RS decoding of a selection header having the variable length may not be effectively performed in a receiving device. That is, when an encoding is performed using the shortened RS code scheme in a sending device, bits having a value of ‘0’ may be added to match a mother code length in the receiving device, and then the RS decoding may be performed. However, when receiving the selection header having the variable length, a number of bits having the value of ‘0’ that are required to be added is unknown.
In a conventional High Speed Internet (HSI) PHY standard, the basic header including the PHY header, the MAC header, and the HCS field may be encoded using the shortened LDPC code scheme in the same manner as that in the above described SC PHY standard. The conventional HSI PHY standard may encode a selection header including the MAC subheader and the HCS field using the shortened LDPC code scheme.
In the HSI PHY standard, similar to the above described SC PHY standard, the selection header may have a variable length. Accordingly, the variable length may cause a problem in that an LDPC decoding of the selection header having the variable length may not be effectively performed in a receiving device. That is, when an encoding is performed using the shortened LDPC code scheme in a sending device, bits having a value of ‘0’ may be added to match a mother code length in the receiving device, and then the LDPC decoding may be performed. However, when receiving the selection header having the variable length, a number of bits having the value of ‘0’ that are required to be added is unknown.
In a conventional Audio Video (AV) PHY standard, a High rate protocol (HRP) header, an extended MAC header, and the HCS field may be divided into two information byte blocks. The respective divided information byte blocks may be encoded using the shortened RS code scheme.
The extended MAC header may have a variable length since an MAC extension header field, a security header field, and a video header field may or may not exist in the extended MAC header. Nevertheless, in a conventional art, information including the HRP header, the extended MAC header, and the HCS may be considered to have a 92 byte fixed length, be divided into 48 bytes and 44 bytes, and then have the divided information blocks individually encoded using the shortened RS code scheme. Accordingly, when encoding/decoding a second information block having the variable length, an encoder and decoder may cause an error.